1. Technical Field
The invention relates to woodworking tools, and in particular, to an apparatus for sharpening woodworkers' chisels, plane blades, various turning tools, etc. More particularly, the invention relates to an apparatus for use with sharpening stones and honing films for sharpening the beveled edges of a woodworking tool.
2. Background Information
Various devices have been used for sharpening the edges of woodworking tools, such as chisels, plane blades and certain types of turning tools. Many of these tools have a blade with a beveled edge which requires occasional sharpening by removing a certain amount of material from the beveled edge to maintain a sharp edge and the cutting efficiency of the tool. One common method of sharpening tool blades is by manually holding the cutting tool blade and bringing it into sliding contact with a sharpening stone or a honing film depending upon the particular cutting edge and use of the tool.
Various devices have been developed to assist in the sharpening process such as shown in U.S. Pat. No. 6,926,596 which uses a device which holds the tool at a predetermined adjusted angle and then rotates an abrasive surface for sharpening the cutting edge. Another type of tool blade sharpening apparatus is shown in U.S. Pat. No. 4,733,501 wherein the tool blade is clamped at a preset angle on a roller mechanism which is then moved along the abrasive surface. Although these devices, as well as other known sharpening apparatus and methods, have proved satisfactory, it has been found that the manual sharpening of the tool working blade requires skill on part of the user, which is not possessed by many amateur woodworkers, and prior art sharpening apparatus have proved difficult to operate to achieve the desired sharpening.
It is also desirable that the sharpening apparatus be able to accommodate various widths and types of cutting tools without requiring additional components which are subject to loss or misplacement. Furthermore, it is desirable that the sharpening tool can be used with an abrasive surface having a relatively large area, both longitudinally and laterally, to accommodate blades of various widths and avoid always using a very small portion of the abrasive sharpening surface thereby shortening the usefulness of the sharpening stone or honing film.
Furthermore, many of the known prior devices enable the primary angle of the beveled cutting edge to be sharpened, but are difficult to sharpen the smaller secondary angle which is part of many types of cutting edges which, for example, may be 2% off the primary angle.
Therefore, the need exists for an improved method and apparatus for sharpening tool blades which can be used both by a skilled or unskilled woodworker, enabling both primary and secondary angles to be sharpened and formed on the beveled edge of the cutting blade in a simple effective manner without the removal of excess blade material to achieve the sharpened edge.